In the summer of 1979, a new clinical syndrome in infants less than 10 months of age characterized by poor appetite, failure to thrive, hypochloremia and varying degrees of metabolic alkalosis was described in association with the feeding of a chloride deficient formula, Neo-Mull-Soy. Twenty-two of the approximately 148 infants, reported to and confirmed by the Center for Disease Control as having this syndrome have been studied since long-term effects of chloride deficient feedings in humans are not known. Evaluation at an average of 24-28 mo. of age demonstrated normal routine blood chemistries and a normal metabolic response to alterations of sodium intake. Other underlying known metabolic disorders have not been identified. Repeat evaluations with emphasis on psychometric testing are currently being performed. At the present time there is no common characteristic or symptom observed in these infants as a result of the chloride deficient feeding.